1) n. a name for anyone (stereotypically used by male surfters/skaters but now accepted by any race, sex, religion, and wealth)
2) n. something that's just so awesomly cool, amazingly kick ass
3) ?. a way to start a conversation
4) replacing "um" or "like" in any sentence

1) Dude, that guy is soo sexy!
2) Omg! That teacher was so stoned, me and Hil were both like "Duuuude."
3) Dude you have no idea!
4) And then...dude...dude...dude, shit I forgot.